I've looked up ways to solve my problem here on SO and other sources, but nothing i have tried worked, so here i am.
I need to concatenate two tables with different columns, as it follows:
(data is just a represetantion, not my actual data and i'm using Postgres SQL)
Table_1:
name price id location
test 1.0 7 Canada
Table_2
name store sale price location
testing local_store 54 2.0 US
My actual tables have over 30 rows each, but the resulting table i need would look like this:
Table_concat:
name price store sale id location
test 1.0 null null 7 Canada (row from Table_1)
testing 2.0 local_store 54 null US (row from Table_2)
Basically, i need to put one table on top of another and when the columns do not match, a null value should apear. Can anyone help me?
I can provide further explanation if necessary.
Try this query:
SELECT
name, price, null AS store, null AS sale, id, location
FROM Table_1
UNION
SELECT
name, price, store, sale, null AS id, location
FROM Table_2
Related
Noob question.
Trying to put together a nested query and having some issues.
So I have one table, it contains information on store transactions.
I am trying to pull the store name and value for those stores where there are many occurences.
So something like this made sense to me. I realize that some nested query is needed whereby I need to add something to the where section whereby I pick only those stores that meet the activity condition.
SELECT store, value
FROM table
WHERE group = 'C'
AND (
SELECT store,
count(*) as total_activity
FROM table
WHERE group = 'C'
GROUP BY store
) > 1000
The issue is that I'm not sure how to structure the query.
Expected output would be
store value
101 3442
101 3434
101 3433
102
102
102
..
The table has a store column, so the count just gets a count of their frequency. I just want the rows where the store occurs frequently
SELECT store, value
FROM (
SELECT store, value,
count(*) as total_activity
FROM table
WHERE group = 'C', total_activity > 1000
GROUP BY store )
I currently have a table called tempHouses that looks like:
avgprice | dates | city
dates are stored as yyyy-mm-dd
However I need to move the records from that table into a table called houses that looks like:
city | year2002 | year2003 | year2004 | year2005 | year2006
The information in tempHouses contains average house prices from 1995 - 2014.
I know I can use SUBSTRING to get the year from the dates:
SUBSTRING(dates, 0, 4)
So basically for each city in tempHouses.city I need to get the the average house price from the above years into one record.
Any ideas on how I would go about doing this?
This is an SQL Server approach, and a PIVOT may be a better, but here's one way:
SELECT City,
AVG(year2002) AS year2002,
AVG(year2003) AS year2003,
AVG(year2004) AS year2004
FROM (
SELECT City,
CASE WHEN Dates BETWEEN '2002-01-01T00:00:00' AND '2002-12-31T23:59:59' THEN avgprice
ELSE 0
END AS year2002,
CASE WHEN Dates BETWEEN '2003-01-01T00:00:00' AND '2003-12-31T23:59:59' THEN avgprice
ELSE 0
END AS year2003
CASE WHEN Dates BETWEEN '2004-01-01T00:00:00' AND '2004-12-31T23:59:59' THEN avgprice
ELSE 0
END AS year2004
-- Repeat for each year
)
GROUP BY City
The inner query gets the data into the correct format for each record (City, year2002, year2003, year2004), whilst the outer query gets the average for each City.
There many be many ways to do this, and performance may be the deciding factor on which one to choose.
The best way would be to use a script to perform the query execution for you because you will need to run it multiple times and you extract the data based on year. Make sure that the only required columns are city & row id:
http://dev.mysql.com/doc/refman/5.0/en/insert-select.html
INSERT INTO <table> (city) VALUES SELECT DISTINCT `city` from <old_table>;
Then for each city extract the average values, insert them into a temporary table and then insert into the main table.
SELECT avg(price), substring(dates, 0, 4) dates from <old_table> GROUP BY dates;
Otherwise you're looking at a combination query using joins and potentially unions to extrapolate the data. Because you're flattening the table into a single row per city it's going to be a little tough to do. You should create indexes first on the date column if you don't want the database query to fail with memory limits or just take a very long time to execute.
EDIT: I'm using the PROC SQL functionality in SAS.
I'm trying to overwrite data in a primary table with data in a secondary table if two IDs match. Basically, there is a process modifying certain values associated with various IDs, and after that process is done I want to update the values associated with those IDs in the primary table. For a very simplified example:
Primary table:
PROD_ID PRICE IN_STOCK
1 5.25 17
2 10.24 200 [...additional fields...]
3 6.42 140
...
Secondary table:
PROD_ID PRICE IN_STOCK
2 11.50 175
3 6.42 130
And I'm trying to get the new Primary table to look like this:
PROD_ID PRICE IN_STOCK
1 5.25 17
2 11.50 175 [...additional fields...]
3 6.42 130
...
So it overwrites certain columns in the primary table if the keys match.
In non-working SQL code, what I'm trying to do is something like this:
INSERT INTO PRIMARY_TABLE (PRICE, IN_STOCK)
SELECT PRICE, IN_STOCK
FROM SECONDARY_TABLE
WHERE SECONDARY_TABLE.PROD_ID = PRIMARY_TABLE.PROD_ID
Is this possible to do in one statement like this, or will I have to figure out some workaround using temporary tables (which is something I'm trying to avoid)?
EDIT: None of the current answers seem to be working, although it's probably my fault - I'm using PROC SQL in SAS and didn't specify, so is it possible some of the functionality is missing? For example, the "FROM" keyword doesn't turn blue when using UPDATE, and throws errors when trying to run it, but the UPDATE and SET seem fine...
Do you really want to insert new data? Or update existing rows? If updating, join the tables:
UPDATE PT
SET
PT.PRICE = ST.PRICE,
PT.IN_STOCK = ST.IN_STOCK
FROM
PRIMARY_TABLE PT JOIN SECONDARY_TABLE ST ON PT.PROD_ID = ST.PROD_ID
One answer in SAS PROC SQL is simply to do it as a left join and use COALESCE, which picks the first nonmissing value:
data class;
set sashelp.class;
run;
data class_updates;
input name $ height weight;
datalines;
Alfred 70 150
Alice 59 92
Henry 65 115
Judy 66 95
;;;;
run;
proc sql;
create table class as select C.name, coalesce(U.height,C.height) as height, coalesce(U.weight,C.weight) as weight
from class C
left join class_updates U
on C.name=U.name;
quit;
In this case though the SAS solution outside of SQL is superior in terms of simplicity of coding.
data class;
update class class_updates(in=u);
by name;
run;
This does require both tables to be sorted. There are a host of different ways of doing this (hash table, format lookup, etc.) if you have performance needs.
Try this:
INSERT INTO PRIMARY_TABLE (PRICE, IN_STOCK) VALUES
(SELECT PRICE, IN_STOCK
FROM SECONDARY_TABLE
JOIN PRIMARY_TABLE ON SECONDARY_TABLE.PROD_ID = PRIMARY_TABLE.PROD_ID)
The only reason you would have to use an INSERT statement is if there are IDs present in the secondary table and not present in the primary table. If this is not the case then use a regular UPDATE statement. If it is the case then use the following:
INSERT INTO PRIMARY_TABLE (ID, PRICE, IN_STOCK)
SELECT ID, PRICE, IN_STOCK
FROM SECONDARY_TABLE s
ON DUPLICATE KEY UPDATE PRICE = s.PRICE, IN_STOCK = s.IN_STOCK
I have two tables say A and B. A has many columns like Date, Customer, Price, typedesc etc. B has only one column typedesc. I want to retrieve rows in A whose typedesc is in B. So I wrote
select * from A where typedesc in (select typedesc from B)
I got 0 rows in result. So i tried
select A.* from A inner join B on A.typedesc=B.typedesc
Still I am getting 0 rows in result
I manually checked the typedesc column in both tables, there are matching entries. typedesc contains strings and it is of type varchar2
Here are the sample tables
A
DATE CUSTOMER TYPEDESC SKU PRICE
02/01/2013 4567 CREAM CORDIALS 1234 23
03/01/2013 3256 U.S. BRANDY 3322 10.5
B
TYPEDESC
CREAM CORDIALS
FIRE WHISKY
Try to use the TRIM function before comparison to avoid the mismatch due to extra spaces.
This is staight forward I believe:
I have a table with 30,000 rows. When I SELECT DISTINCT 'location' FROM myTable it returns 21,000 rows, about what I'd expect, but it only returns that one column.
What I want is to move those to a new table, but the whole row for each match.
My best guess is something like SELECT * from (SELECT DISTINCT 'location' FROM myTable) or something like that, but it says I have a vague syntax error.
Is there a good way to grab the rest of each DISTINCT row and move it to a new table all in one go?
SELECT * FROM myTable GROUP BY `location`
or if you want to move to another table
CREATE TABLE foo AS SELECT * FROM myTable GROUP BY `location`
Distinct means for the entire row returned. So you can simply use
SELECT DISTINCT * FROM myTable GROUP BY 'location'
Using Distinct on a single column doesn't make a lot of sense. Let's say I have the following simple set
-id- -location-
1 store
2 store
3 home
if there were some sort of query that returned all columns, but just distinct on location, which row would be returned? 1 or 2? Should it just pick one at random? Because of this, DISTINCT works for all columns in the result set returned.
Well, first you need to decide what you really want returned.
The problem is that, presumably, for some of the location values in your table there are different values in the other columns even when the location value is the same:
Location OtherCol StillOtherCol
Place1 1 Fred
Place1 89 Fred
Place1 1 Joe
In that case, which of the three rows do you want to select? When you talk about a DISTINCT Location, you're condensing those three rows of different data into a single row, there's no meaning to moving the original rows from the original table into a new table since those original rows no longer exist in your DISTINCT result set. (If all the other columns are always the same for a given Location, your problem is easier: Just SELECT DISTINCT * FROM YourTable).
If you don't care which values come from the other columns you can use a (bad, IMHO) MySQL extension to SQL and do:
SELECT * FROM YourTable GROUP BY Location
which will give a result set with one row per location and values for the other columns derived from the original data in an undefined fashion.
Multiple rows with identical values in all columns don't have any sense. OK - the question might be a way to correct exactly that situation.
Considering this table, with id being the PK:
kram=# select * from foba;
id | no | name
----+----+---------------
2 | 1 | a
3 | 1 | b
4 | 2 | c
5 | 2 | a,b,c,d,e,f,g
you may extract a sample for every single no (:=location) by grouping over that column, and selecting the row with minimum PK (for example):
SELECT * FROM foba WHERE id IN (SELECT min (id) FROM foba GROUP BY no);
id | no | name
----+----+------
2 | 1 | a
4 | 2 | c